LCD Common Electrode Switching to Prevent Power-On Flicker
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Solution Overview
Problem
Conventional LCDs experience an instantaneous flickering phenomenon during power-on due to capacitive coupling between data and signal lines, causing abnormal voltage differences across liquid crystal molecules.
Innovation Solution
A display device with a switch controller connected between the common voltage pin and common electrode, controlled to turn on the circuit after a first time point, along with a timing controller to manage data signal output and switch control signals, preventing voltage differences by stabilizing the common electrode potential.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the common voltage signal is transmitted to the common electrode before the data latch signal is received, then the common electrode potential is stabilized early, but capacitive coupling causes abnormal voltage differences across liquid crystal molecules resulting in instantaneous flickering
Solution Approach 1:
The patent applies preliminary action by delaying the transmission of the common voltage signal to the common electrode until after the data latch signal is received. The switch controller is configured to transmit the common voltage signal only when the timing controller detects that the data latch signal has been received, ensuring that the common electrode potential is stabilized at the appropriate moment to avoid capacitive coupling issues that would cause flickering.
Solution Approach 2:
The patent implements feedback through the timing controller that monitors the reception of the data latch signal and uses this information to control the switch controller. The switch controller receives control signals from the timing controller based on the data latch signal status, creating a feedback mechanism that ensures the common voltage signal is transmitted only when conditions are appropriate, thereby preventing instantaneous flickering.
2Loss of time
If the common voltage signal is transmitted early to stabilize common electrode potential, then the display can initialize faster, but voltage differences become abnormal causing display flickering
Solution Approach 1:
The patent applies preliminary action by preparing the switch controller to transmit the common voltage signal immediately upon receiving the data latch signal. This ensures that the common electrode potential is stabilized at the optimal moment - not too early to cause flickering, but as early as possible to minimize initialization time loss.
Solution Approach 2:
The switch controller acts as an intermediary between the voltage generator and the common electrode. It mediates the transmission of the common voltage signal by controlling when the signal is transmitted based on the data latch signal status, thus balancing the need for fast initialization with the need to avoid flickering caused by premature voltage application.
3Object-affected harmful factors
If a switch controller is added to control common voltage transmission timing, then instantaneous flickering is prevented, but device complexity increases
Solution Approach 1:
The switch controller is designed with multi-functionality, serving both as a voltage transmission gate and as a timing-synchronized control element. It receives control signals from the timing controller and automatically synchronizes the common voltage signal transmission with the data latch signal, eliminating the need for separate control circuits and reducing overall system complexity despite adding functional capability.
Solution Approach 2:
The patent merges the switch controller's functions with the existing timing control architecture. The switch controller is integrated into the signal transmission path and coordinated with the timing controller, combining voltage control and timing functions in a unified approach that minimizes additional complexity while effectively preventing instantaneous flickering.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively prevents instantaneous flickering by stabilizing the common electrode potential, ensuring stable voltage differences and normal display operation upon power-on.
Implementation Method 1
due to capacitive coupling between a data line transmitting an invalid voltage and a signal line transmitting another signal before the operation described above, a voltage on the data line may be changed
Data Source
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AI summary
A display device and a driving method thereof are provided. A source driver in the display device is configured to transmit data signals to a plurality of sub-pixels, the data signals including a second data signal (for controlling the brightness of a display panel at the sub-pixels) located after a first time point, a voltage generator in the display device includes a common voltage pin for outputting the common voltage signal, and a switch controller connected between the common voltage pin and the common electrode is configured to turn on a circuit between the common voltage pin and the common electrode after the first time point, thereby improving an instantaneous flickering phenomenon at the time of powering on the display device.